Unmanned aerial systems (“UASs”) or unmanned aerial vehicles (“UAVs”), such as vertical take-off and landing (“VTOL”) aircraft, quadcopters and helicopters, and fixed-wing aircraft requiring runways for take-off and landing, are often deployed for military, policing, and firefighting applications, as well as for nonmilitary surveillance work. While UAVs have traditionally been effective for short-duration missions, particularly in regions where their batteries can be quickly replaced, they have not been effectively utilized for longer-duration missions, especially when deployed in regions remote from humans.